Problems with "mr Barry " battery relocation kit

[silverspeed]

The last couple of weeks my 4 has become impossible to start while warm and with the fans on.. Everytime I visited a petrol station I knew the car wouldn't start untill it was uber cool which made me look a right lemon. So I started to investigate the problem.. First I changed the starter motor.. Then the battery..with no joy.! Then I checked the charge current from the alternator.. 13.4 volts.. Then checked the current to the battery while the engine was running.. 13.1 volts which I found strange.  then I tried turning over the engine to see the drop in current.. was rediculously poor 9 volts under cranking!!!!!
I then decided to bypass the starter solinoid.. Made a good improvement to the point of starting at the petrol station but only just.. I then decided to completely remove the "mr Barry" relocation kit and make my own.  After stripping the car to bits I found the cable povided in the kit scorched/melted  about a meter before the starter switch.. Causing it to short out under cranking!! ( thought I could smell burning)  I've just completed a full rewire (minus start switch) and hey presto..  Starts/cranks almost straight away   

[Driveby]

Had the cable rubbed through causing the short?  Was it an installation error
Ive fitted 3 of these and not had any problems at all.

[silverspeed]

  it was definatley burnt and not rubbed as it was the straight  part located behind the speakers.. I'm guessing the switch had become faulty.. I've spoken to a few now who have removed it and just replaced it with a fuse.. Should of taken note sooner I suppose it could have been worse.. It could have burnt behind the dash and melted some wires. 

[Chris_de_Bear]

Was the burnt cable at a junction / onto a component ? From the rest of the post it sounds like a trip used rather than a fuse. I have had major problems with trips in the past and only use fuses now.

If the cable has burnt mid-cable without the entire cable being burnt, then it is most likely where is passes through a thermally insulating area e.g between carpet and underlay, or has passed over an edge which has pierced the insulation and caused arcing.

Volt drop along cable is normal, as all cable has resistance. The thicker the cable, the less resistance therefore less volt drop and less heating, therefore higher current rating.

I'm not familliar with the Mr. Barry kit so without more detailed answers to the above I can't really comment further.

[silverspeed]

The cable looks like a split banna skin.. With burnt edges. A 100 amp fuse was used (same ampage as the alt fuse in the fuse box.) between battery and start solinoid.. The burst/split/burnt wire was about 2ft the other side between starter solinoid and starter motor.. The cable was run behind the speaker location, on the rear inner wing with p clips to hold it inplace..(speakers/speaker box surround sound thingy removed completely)  All connections were properly soldered and crimped and then taped, heatshrunk. Their was no movement in the wire or anything that could rub it.. (me not silly  )  when I replaced everything I doubled checked all earthing points and the extra 2 I added.. Nothing was out of place.  I either had a power surge ( which should have killed the fuse our alt fuse or the starter solinoid was duff.. Or poor sized cable???